• Proceedings of the KWS Conference
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• 2002.10a
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• pp.176-180
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• 2002

During the last two decades the laser beam has progressed from a sophisticated laboratory apparatus to an adaptable and viable industrial tool. Especially, in its welding mode, the laser offers high travel speed, low distortion, and narrow fusion and heat-affected zones (HAZ). The principal obstacle to selection of a laser processing method in production is its relatively high equipment cost and the natural unwillingness of production supervision to try something new until it is thoroughly proven. The major objective of this work is focused on the combined features of gas tungsten arc and a low-power cold laser beam. Although high-power laser beams have been combined with the plasma from a gas tungsten arc (GTA) torch for use in welding as early as 1980, recent work at the Ohio State University has employed a low power laser beam to initiate, direct, and concentrate a gas tungsten arcs. In this work, the laser beam from a 7 watts carbon monoxide laser was combined with electrical discharges from a short-pulsed capacitive discharge GTA welding power supply. When the low power CO laser beam passes through a special composition shielding gas, the CO molecules in the gas absorbs the radiation, and ionizes through a process known as non-equilibrium, vibration-vibration pumping. The resulting laser-induced plasma (LIP) was positioned between various configurations of electrodes. The high-voltage impulse applied to the electrodes forced rapid electrical breakdown between the electrodes. Electrical discharges between tungsten electrodes and aluminum sheet specimens followed the ionized path provided by LIP. The result was well focused melted spots.

• International Journal of CAD/CAM
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• v.6 no.1
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• pp.183-192
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• 2006

A CAD/CAM system has been developed for rapid prototyping (RP) of microfluidic devices based on excimer laser micromachining. The system comprises of two complementary softwares. One, the CAM tool, creates part programs from CAD models. The other, the Simulator Tool, uses a part program to generate the laser tool path and the 2D and 3D graphical representation of the machined microstructure. The CAM tool's algorithms use the 3D geometry of a microstructure, defined as an STL file exported from a CAD system, and process parameters (laser fluence, pulse repetition frequency, number of shots per area, wall angle), to automatically generate Numerical Control (NC) part programs for the machine controller. The performance of the system has been verified and demonstrated by machining a particle transportation device. The CAM tool simplifies part programming and replaces the tedious trial-and-error approach to creating programs. The simulator tool accepts manual or computer generated part programs, and displays the tool path and the machined structure. This enables error checking and editing of the program before machining, and development of programs for complex microstructures. Combined, the tools provide a user-friendly CAD/CAM system environment for rapid prototyping of microfluidic devices.

• Laser Solutions
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• v.11 no.3
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• pp.10-15
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• 2008

This study is aimed to analyse the laser glass bonding process numerically. Due to the viscoelastic behaviour of glass, the extremely large deformation of the frit seal is resulted continuously over the transition temperature, so that the thermal boundary condition be changed in the entire calculation process. The commercial FEM algorithm is restrictively able to remesh the large geometrical boundary shape and to adapt the boundary conditions simultaneously. According to our manual adaptation of increasing the laser line intensity to 700 mW/mm, it is possible to estimate the thermal glass bonding process under the fracture stress in principle. But it should be studied further in the case of high laser line intensity.

• Laser Solutions
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• v.13 no.4
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• pp.14-20
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• 2010

Robot path generation and laser welding technology for manufacturing automotive body are studied. Laser welding and industrial robot systems are used with the robot based laser welding system. The laser system used in this study is 1.6kW Fiber laser, while the robot system is 6 axes Industrial robot (payload: 130kg). The robot based laser welding system is equipped with laser scanner system for remote laser welding. The laser source, robot and laser scanner system are used to increase the processing speed and to improve the process efficiency. The welding joints of steel plate are butt and lapped joints. The quality test of the laser welding are through the observation the shape of bead on plate and cross-section of welding part. The 3 dimensional laser welding for non-linear pipe welding line is performed. This paper introduces the robot based laser welding system to resolve the limited welding speed and accuracy of the conventional spot welding system.

• Proceedings of the Korean Magnestics Society Conference
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• 2010.06a
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• pp.40-40
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• 2010

• Proceedings of the Optical Society of Korea Conference
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• 1989.06a
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• pp.107-115
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• 1989

A 200 W industrial Nd:YAG laser was developed and its weding applications were investigated. The important factors in designing of an industrial Nd:YAG laser were analyzed and special sedign features were explained. Also, the performance of laser weldings of Zircaloy-4, stainless steel and fine thermocouples was presented.

• Proceedings of the Optical Society of Korea Conference
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• 1989.02a
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• pp.32-35
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• 1989

A 150W industrial Nd:YAG laser was developed. The thermal lensing effect was examined and the radius and position of rear mirror were optimized for higher efficiency. The efficiency of 2.5% was achieved. Also, the performance of laser welding in fine thermocouples and between high-temperature-melting dissimilar metals were investigated.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.11
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• pp.975-982
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• 2010

In this study, the laser sintering of inkjet-printed silver lines was evaluated. Silver-nanoparticle ink and a drop-ondemand (DOD) inkjet printer were used for printing on glass and polyethylene terephthalate (PET) substrates with various thicknesses. To sinter the printed silver nanoparticles, the silver layer printed on the transparent substrates was irradiated by focused CW laser beams that were incident normal to the substrates; the irradiation was carried out for various beam intensities and for various irradiation times. The electrical conductivity of the laser-sintered silver patterns was measured and compared with the conductivity of silver patterns sintered by using an oven. The increase in the temperature caused by laser irradiation was also calculated on the basis of the laser beam intensity, irradiation time, surface reflectivity, and thermophysical property of the substrate in order to estimate the increase in the electrical conductivity caused by laser sintering.

• IEMEK Journal of Embedded Systems and Applications
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• v.15 no.2
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• pp.79-85
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• 2020

IIoT stands for Industrial Internet of Things used in manufacturing, healthcare, and transportation in networked smart factories. Recently, IIoT's environment requires an automated control system through intelligent cognition to improve efficiency. In particular, IIoT can be applied to automatic calibration of production equipment for improved management in industrial environments. Such automation systems require a wireless network for transmitting industrial data. Self-calibration systems in laser transmission paths using wireless networks can save resources and improve production quality by real-time monitoring and remote control of laser transmission path. In this paper, we propose a wireless networked system for self-calibration of laser equipment that requires a laser transmission path, and we show the results of the prototype evaluation. The self-calibration system of laser equipment measures the coordinates of the laser points with sensors and sends them to the host using the proposed application protocol. We propose a wireless network service for the wired motor controller to align the laser coordinates. Using this wireless network, the host controls the motor by sending a control command of the motor controller in an HTTP message based on the received coordinate values. Finally, we build a prototype system of the proposed design to verify the detection performance and analyze the network performance.

• Journal of Welding and Joining
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• v.31 no.6
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• pp.58-64
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• 2013

Several joining methods involving resistance welding, laser welding, ultrasonic welding and mechanical joining are currently applied in manufacturing lithium-ion batteries. Cu and Al alloys are used for tab and bus bar materials, and laser welding characteristics for these alloys were investigated with similar and dissimilar material combinations in this study. The base materials used were Al 1050 and oxygen-free Cu 1020P alloys, and a disk laser was used with a continuous wave mode. In bead-on-plate welding of both alloys, the joint strength was higher than the strength of O tempered base material. In overlap welding, the effect of welding parameters on the tensile shear strength and bead shape was evaluated. Tensile shear strength of overlap welded joint was affected by interfacial bead width and weld defect formation. The tensile-shear specimen was fractured at the heat affected zone by selecting proper laser welding parameters.